Japanese Patent Application Laid-Open No. 2002-290940 (Patent Document 1) introduces a video conference system in which a server, which is arranged in a network, temporarily receives a video stream transmitted from each terminal and then delivers the video stream to all terminals. In this mode, the server receives video data from all terminals respectively and delivers the video data to each terminal. Each terminal decodes a plurality of received video streams and displays them in a predetermined display format for video conferencing such as an equally divided screen composed display and a close-up of the speaker.
Also, a mode is known in which the server in the network decodes all video data received from each terminal, encodes the vide data after performing necessary image processing, and transmits only a video stream in response to a request from each terminal. According to this mode, the server can process video streams considering performance of the terminals and therefore, there is an advantage that the encoding method, encoding settings, options and the like can arbitrarily be set.    Patent Document 1: Japanese Patent Application Laid-Open No. 2002-290940